Association between cognitive performance and cortical glucose metabolism in patients with mild Alzheimer's disease

Background: Neuronal and synaptic function in Alzheimer's disease
(AD) is measured in vivo by glucose metabolism using positron
emission tomography (PET). Objective: We hypothesized that neuronal
activation as measured by PET is a more sensitive index of neuronal
dysfunction than activity during rest. We investigated if the
correlations between dementia severity as measured with the Mini
Mental State Examination (MMSE) and glucose metabolism are an
artifact of brain atrophy. Method: Glucose metabolism was measured
using {[}F-18]fluorodeoxyglucose PET during rest and activation due
to audiovisual stimulation in 13 mild to moderate AD patients (MMSE
score >= 17). PET data were corrected for brain atrophy.
Results: In the rest condition, glucose metabolism was correlated
with the MMSE score primarily within the posterior cingulate and
parietal lobes. For the activation condition, additional
correlations were within the primary and association audiovisual
areas. Most local maxima remained significant after correcting for
brain atrophy. Conclusion: PET activity measured during audiovisual
stimulation was more sensitive to functional alterations in glucose
metabolism in AD patients compared to the resting PET. The
association between glucose metabolism and MMSE score was not
dependent on brain atrophy. Copyright (C) 2005 S. Karger AG, Basel.